SiC (silicon carbide) is expected to be a material for next-generation power semiconductor devices. SiC has excellent physical properties, having a band gap three times wider than that of Si (silicon), a breakdown field strength approximately 10 times higher than that of Si, and a heat conductivity approximately three times higher than that of Si. A power semiconductor device that has low loss and is capable of high-temperature operation can be realized by taking advantage of those properties.
With SiC, however, it is difficult to lower the resistance of a p-type impurity layer or an n-type impurity layer, because the solid solubility limit of the impurity is low, and the levels formed with the impurity in the band gap are deep.